1. Field of the Invention
The present invention relates to a roller adapted to convey a metal mould of an injection moulding machine and the like in the horizontal direction.
2. Description of the Prior Art
Among such conveying rollers, conventionally there are ones disclosed in Japanese Utility Model Publication No. 59-140821. The following two conventional embodiments are described in the publication.
As shown in FIG. 6, a conveying roller 60 of a first conventional embodiment is constructed as follows.
A threaded hole 79 and a circular bore 80 are formed coaxially in series in a fixed plate 51 of an injection moulding machine. A support cylinder 62 is constructed by a supporting portion 72 adapted to be fitted into tile circular bore 80 and a bearing portion 73 adapted to rotatably support a roller member 64 through a bearing 63. An axis of the supporting portion 72 is offset relative to an axis of the bearing portion 73. A bolt 66 is fitted into a cylindrical bore 65 of the support cylinder 62 coaxially to the supporting portion 72 and a leg portion 66a of the bolt 66 is threadably engaged with the threaded hole 79.
When a level of the roller member 64 is adjusted, the bolt 66 is loosened a little and the support cylinder 62 is rotated by a desired angle relative to the bolt 66 under that condition so as to change a height position of a top portion of the roller member 64. After that, the bolt 66 is tightened so as to press and secure the support cylinder 62 to a fixed plate 51 by its head portion 66b.
As shown in FIG. 7, in a conveying roller 60 of a second conventional embodiment, the supporting portion 72 of the first conventional embodiment is omitted from the support cylinder 62 and a midway portion of the bolt 66 is fitted into the circular bore 80. Other construction and the level adjusting method are the same as those in the first conventional embodiment.
In the respective conventional embodiments, when the conveying roller is mounted to the installed infection moulding machine, it is necessary to form the threaded hole 79 and the circular bore 80 in the fixed plate 51 on the working spot by means of a hand drill and so on.
Accordingly, there are the following problems associated with the first conventional embodiment ( refer to FIG. 6 ).
In order that the circular bore 80 rotatably supports the supporting portion 72 of is the support cylinder 62, it is necessary to finish the peripheral surface of the bore 80 with a high accuracy and to form the bore 80 coaxially to the threaded hole 79. Therefore, it is very difficult to carry out the machining in the working spot. As a result, it is troublesome to mount the conveying roller 60.
If the bolt 66 happens to be loosened even a little during conveying of a metal mould 55, the support cylinder 62 is subjected to a shock caused by the metal mould 55 to swing eccentrically about the bolt 66. Thereupon, the height position of the roller member 64 gets out of order. Therefore, it is apprehended that the metal mould 55 can't be conveyed smoothly.
In the second conventional embodiment ( refer to FIG. 7), since the bolt 66 is fitted into the circular bore 80, it is not necessary to hold a high finish accuracy for the peripheral surface of the circular bore 80 in comparison with the first conventional embodiment. But, since it is necessary to form the circular bore 80 coaxially to the threaded hole 79, it is still difficult to carry out the machining in the working spot.
Also in this second conventional embodiment, similarly to the first conventional embodiment, the height position of the roller member 64 gets out of order due to a swing of the support cylinder 62.